A trigger is something usually an electrical signal that is used to get a pump to change it’s pumping action.
Simplest example is the use of a foot switch on a manual production line. For example an ink cartridge refiller. They pick up a print cartridge for filling, insert the filling probe into the cartridge and the press the foot switch (with their foot). The pump then begins to run a pumping program which fills the ink cartridge at a safe rate for a known volume. Every print cartridge is filled the same following the foot switch trigger.
The pumps on this website all support external signal triggering from ttl logic level signals.
The triggers can be the rising or falling of the signal input level. These triggers can be configured to jump to two different sections of a pump program – thus implementing two separate pumping actions based on the input signal applied. For example you could have two sections one for a slow flow and anther for a fast flow – the trigger could switch between the flow rates.